1. Field of the Invention
The present invention relates to an apparatus and a method for adsorbing and recycling material in a blending operation. More particularly, the apparatus and method relates to adsorbing and recycling hazardous materials during blending operations.
2. Description of the Prior Art
In the production of many articles of commerce, toxic material are important intermediates for compositions useful in agriculture and in a wide variety of manufacturing industries, For example, the solution of catechol (1,2-dihydroxybenzene) in monoethanolamine (2-aminoethano) is utilized for removing photoresists from printed circuit boards. Catechol is corrosive and toxic, and a particular caution is required in handling because it can be readily absorbed through the skin. Further, the vapor of catechol can also affect the eyes and mucous membranes. Likely, overexposure to monoethanolamine effects the respiratory system, and can cause problems to the skin and cause eye irritation. In order to avoid the above-mentioned problems, when it is in the proximate environment safety equipment must be used, i.e., face shield, gloves and a vapor impervious apron of a xe2x80x9cHAZMATxe2x80x9d suit, Thus, a need exists for an improved, efficiently simple and cost effective method and apparatus for blending toxic materials. Particularly an apparatus and method that are sufficiently fast to be capable of handling, especially thermally sensitive and/or toxic is quite apparent. The need is met by a process and apparatus as disclosed herein which generally improves upon the prior art techniques described above.
Generally stated, the present invention improves upon a blending operation in which components and product loss are substantially eliminated by recovering materials from various units of the apparatus, and recycling the materials back to the respective units. More particularly, the method and apparatus of this invention are directed to the mixing of toxic materials wherein the recovery/recycling operation have the inherent benefits of reducing the hazardous conditions in the workplace and of allowing the exhaust streams from the various units to be discharged into the atmosphere well within the limits of federal and state statutes. The method and apparatus are most particularly useful in blending toxic materials when the dissolving process is exothermic. It follows that in an exothermic system more volatiles are suspended in the exhaust stream. The method of the invention in its broadest aspect is achieved by a blending operation, which comprises the steps of:
a.) introducing a solvent into a closed mixing vessel having at least one vent in fluid communication with at least one demister device;
b.) agitating said solvent;
c.) charging a solute into said solvent;
d.) dissolving said solute into said solvent to form a solute product and vapor entraining both solvent and solution product;
e.) exhausting said vapor from the mixing vessel to said demister device
f.) passing said vapor through said demister device removing the entrained substances from the vapor, forming droplets and returning the droplets back to said mixing vessel;
g.) discharging the treated vapor to the atmosphere; and
h.) transferring solution product from the mixing vessel.
In accordance with an apparatus aspect of the present invention said apparatus comprises:
a.) a closed conveyor conduit assembly for supplying a solute which includes a hopper device in combination with a helical conveyor, said hopper device having a chamber including a blower assembly mounted within said chamber, a removably attached high efficiency particulate air filter, and an outlet which is connected with a hopper vent, said filter being operatively connected to the blower assembly, a first vent means in fluid communication with an exhaust to the atmosphere, a closed vessel for holding and mixing solvent having a inlet means for introducing solvent into said vessel, a mixing means, an outlet means for discharging solution product, and a demister device in fluid communication with said second vent means.
It is, therefore, an object of this invention to provide an improved method and apparatus for blending solute-solvent systems, which increases the efficiency of the operation by substantially eliminating starting material and product loss, and reducing capital expenditures and operating expenses.
It is another object of this invention to provide an improved method and apparatus for blending toxic materials by removing harmful substances from the blending units making the workplace safer.
A further object of this invention is to provide an improved method and apparatus for blending toxic materials which substantially eliminates starting material and product loss, as well as, provides efficient removal of harmful vapors exhausted from the blending process which may be discharged to the atmosphere without stress to the environment.
Yet another object of this invention is to provide an improved method and apparatus for safely and efficiently blending toxic materials, improved safety throughout the moving environment and increased productivity without a large expenditure of capital.
It is still a further object of this invention to provide a method and apparatus, which is more easily operated and maintained.
Another object of the invention is to provide an improved method and apparatus for the blending of catechol and monoethanolamine and for removing efficiently and economically harmful materials from the vapors exhausted from the blending procedure.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part, will become apparent to those skilled in the art upon examination of the following or may be learned by the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.